Variable-stroke fuel pump



Jan. 7, 193() J. ZUBATY VARIABLE STROKE FUEL PUMP Filed June 22, 1928Patented Jan. 7, 1930 UNITED STATES PATENT OFFICE JOSEPH ZUBATY, OFFLINT, MICHIGAN, ASSIGNOR T C SPARK` PLUGv COMPANY, OF

FLINT,`MICHIGAN, A COMPANY OF MICHIGAN VARIABLE-STROKE FUEL PUMPApplication led J'une 22,

This invention relates to variable stroke fuel pumps suitable for useupon automotive vehicles, or elsewhere in connection with internalcombustion engines or the like; and

it is a particular object of this invention, in

a preferred embodiment thereof, dispensing with an linkage or similarthrust-refusing interme 'ate means for the transmission of motion froman oscillatory lever, or the like, to a pumping element, to provide anovel and conditionall rigid lever or rocker arm, suitable for usebetween a reciprocatory or rotating part and a pump diaphragm stem,'o1-

the likesaid lever comprising a conditionally resilient arm or sectionwhich includes a part that may so constantly engage said reciprocatoryor rotating part (as,.an engine crankshaft) as substantially to avoidContact noises.

Although the present invention is herein described with particularreference to adiaphragm pump similar to that described and claimed 1n apending application of Abraham M. Babitch, Serial No. 123,370, led July19, 1926, it should be understood that the principles of this inventionare believed to be applicable to other reciprocatory pumps in whichprovision is made for the use of resilient means to effect expulsionstrokes, the intake strokes thereof being variable in length and beingeected through the mentioned resilient arm or a like part and beingdiminished in length as pressure is built up within a pum chamber; andit is a particular object of t is invention to provide pump operatinmeans which may not only obviate avoi able noises, such as areincidental to the operation of known types of thrust-refusingintermediate mechanism, but also substantially obviate all necessity forany rocking of the mentioned lever, or its equivalent, after asufficient pressure has been built up withina pump chamber.

Other objects of this invention, most or all forms of which may involvethe use of a lever or a rocking or other reciprocatory member whichbecomes increasingly iniiexible as increased pressures are applied to aninitially resilient part thereof, may be best appreciated from thefollowing description 1928. Serial No. 287.625.

of an illustrative embodiment of said invention, taken in connectionwith the appended claims and the accompanying drawings.

Fig. 1 may be referred to as a substantially median section through onefuel pump illustrative of this invention.

Fig. 2 is a partial view corresponding to the lower portion of Fig. 1,but showing a condition and relationship of parts that may result fromthe building up of a pressure within a pump chamber.

Referring first to conventional parts of the fuel pump selected forpurposes of illustration, a main structural element in the form of abody casting 1 and a subsidiary element in the.v form lof a covercasting 2 are shown as cooperating in the retention of a flexiblediaphragm 3,-adapted to serve as a reciprocatory pumping element byvarying the cubic contents of a pump chamber 4. This chamber is shown asprovided. in the cover casting 2, and said cover casting may be providedwith a valved inlet passage 5 and an outlet passage 5', shown as valvedat 6. Resilient means in the form of a compression spring 7 may tendconstantly to efect expulsion strokes of the diaphragm 3; and intakestrokes ma be imparted theretothrough a flexible or in exible butsubstantially, inex-` tensible tension-transmitting element such as aslidable rod or so-called diaphragm stem 8,-which may berigidlyconnected with the diaphragm 3 or other reciprocatory pumpingelement `by means such as a nut 9 and oppositely concave clampingelements or plates 10 and 10.

A cam 11 upon a shaft 12 (which may be, for example, acrankshaft, or acamshaft. or the like) is intended as representative of anyreciprocating or rotating vpart having a suitable throw, whether uniformor variable, indirectly to impart reciprocatory movement to the rod orstem 8; andthe present inven tion should be understood to relate Iparticularly to the structure and use of anovel actuating element, (shownas an oscillatory lever 13 comprising a resilient part) and a member,such as the rod or stem 8, attached to a reciprocable butpressure-responsive pumping element. For example, the actuating lever13, shown as pivoted at 14 to the casting 1, may comprise a rigid innerarm 15 and a composite outer arm 16. A inand-slot connection beingindicated at 17, the outer and composite arm 16 is shown as comprising arigid part 18 and a flexible part including a leaf spring 19, optionallyj, provided with a contact shoe 20,-the result chamber y a depressedeing a lever which is substantially rigid under certain conditions andnotably resilient under other conditions.

As best indicated in Fig. 2, the resilient part 19, or its equivalent,is intended, in the illusg I tratedembodiment of the present invention,

to `be sc biased toward an angular relationshi to the longitudinal axisof the arm 15, that, the leaf 19 being adapted to serve as a springfinger, the contact shoe 20, if employed, may constantly engage the cam11,-even at times when .a pressure built up within the pump 4 may holdthe rod or stem 8 in such position as to render the rotation of cam 11temporarily ineffective to impart k"further reciprocatory movementthereto.

his construction obviates contact noises and unless the part 18, assumedto be substan- `tially rigid, is of such length as finally to becompletely contacted or pressed upon by the free end ofthe spring linger19 (as, when the 30,

longitudinal axis of the latter is brought into substantial parallelismwith the longitudinal axis of the arm 15) in order to render thecomposite arm 16 substantially unyielding and highly efficient for apumping eli'ect during those periods of normal operation in thereciprocatory pumping element 3 is desired to receive a full stroke (thepresv sure within the chamber 4 being -then insuflicient to hold saidpumping element depressed) additional bent and stepped leaf springs orspring sections may be interposed, as suggested by 21, 22 and 23,between the mentioned spring 19 and the rigid part 18,- means such asrivets 24 being employed to hold the mentioned parts in their intendedrelationship.

It will be understood that, even if rigidly attached to a reciprocatorypumping element, the rod or stem 8 need not be restricted to rectilinearsliding casion use of a pin-andslot connection with the lever 13; butthe spring 7, or equivalent resilient means for effecting expulsionstrokes, is intended in all cases to be of sufficient strength toovercome the conditional resiliency of the arm 16, or itsequivalent,-mov ing the flexible parts thereof into such a relationshipthat, as by reason of actual contact between the respective leaves19,21, 22 and 23, said composite arms may function as if rigid, a-ndsubstantially as implied by the movement such as to ocactuating element13 (assuming this to be a lever) may be moved toward and kept in such adepressed position as to result in a separation of some or'all of theleaves 19, 21, 22, but without causing a se aration of the contact shoe20, if employed, om the cam 11. As soon as the pressure within thechamber 4 drops, it will be understood that some or all of the springleaves 19, 21, 22 and 23 may again be brought into mutual contact; andthe composite arm 16 may again function as if rigid, substantially assuggested in Fig. 1.

It will be noted that, so far as concerns the described mode ofoperation, either or both of the arms 15, 16 ofthe actuating element 13,assuming the latter to have the form of a lever, may be composite andconditionally rigid, increasing in rigidity under increasing upwardressure at the free end or ends thereof; t at the use of separate springleaves, bent to different angular relationships to the axis of the rigidarm 15`and varying in length is essentially a preferred mode ofproviding a slap-preventing spring finger 19, or its equivalent, withgraduated reinforcement; that contact shoe 20, if provided, may or maynot be integral with the spring linger 19; and that all embodiments ofthis invention have, as compared with the usual collapsible linkagesystems, or the like, the advantage that they require only one pivotallymovable member and but few additional parts, these being compactlyarranged, no separate'spring being needed beneath the lever 13, and bothstrokes of the described pump being eifected by or through resilientmeans.

Although the forefgoing description includes a description o but onecomplete embodiment of the present invention, -it should be understoodthat numerous modifications of this invention might easily be devised,without involving the slightest departure from the spirit and scope ofthis invention.

I claim:

1. In a fuel pump comprising a recipro catory pumping element which isprovided with resilient means for conditionally effecting expulsionstrokes thereof: a tensiontransmitting element attached to said umpingelement; and an actuating lever a apted normally to impart intakestrokes to said attached element, said actuating lever comprising aresilient part so rein orced as to increase in ri 'dty under pressure.

2. In a uel pump comprising a reciprocatory pumping element which isprovided with resilient means for conditionally effecting expulsionstrokes thereof a tension-transmitting element attached to said pumpingelement; and an actuating lever adapted normally to impart intakestrokes to said attached element, said actuating lever comprising aresilient part which increases in rigidit under pressure, and becomessubstantia lfylrigid in normal pumping operation.

3. A el pump comprising: a reciprocable pumping element provided withresilient 5 means for e'ecting expulsion strokes thereof and with anattached handling element; and an actuating lever, for said handlinelement, comprislng a spring finger adapted constantly to en age amoving part and provided with gra uated reinforcmg means to increase therigidity thereof upon the :application of increasing pressures thereto.

4. A fuel pump comprising: a reciprocable pumping 'element provided withresilient means for effecting expulsion strokes thereof and with anattached handlin element; and an actuating element, for sai handlingelement, comprising a spring finger adapted constantly to engage amoving part and 2o provided with graduated reinforcing means to increasethe rigidity thereof upon the application of increasing pressuresthereto,- said actuating element having the form of a lever providedwith a substantially rigid arm which is pivotall connected with saidhandling element an also with a composite arm which includes said springfinger.

5. A fuel ump comprising: a reciprocable pumping e ement provided withresilient $0 means for effecting expulsion strokes thereof and with anattached handlin element; and an actuating element, for sai handlinelement, comprising a spring finger adapte constantly to en age a movingpart and provided'with graduated reinforclng means to increase therigidity thereof upon the application of increasing pressuresthereto,-said actuatin element havin the form of a lever rovide with asubstantially rigid arm which 1s pivotally connected not only with saidhandlin element but also with a composite arm whic includes said springfinger and also includes a stepped series of leaves bent toV differentangular relationships to the rigid arm and constituting said gra uatedreinforcing means.

6. A pump comprising: a reciprocable pumpin element having a handlingelement attache thereto; and a lever comprising a 5o conditionallyresilient arm and operatively connected with said handlin element.

In testimony whereof I a my signature.

JOSEPH ZUBATY.

